HFSA: Device Compliance Dips Over Time

Action Points

Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

Point out that the reasons for the decreased compliance over time are not known, and it is not clear that the decreased compliance was associated with adverse effects in this study.

SAN DIEGO -- Poor compliance with wearable external defibrillators (WED) leaves many patients vulnerable to sudden cardiac arrest and may give physicians a false sense of security about their patients, data from a small cohort study suggest.

Compliance with the device declined from 91% of days during the first month of use to 67% in the third month. When defined by the number of hours of use, compliance fell more quickly and to lower levels, such that patients wore the device only about half of the prescribed time during the third month.

"Overall compliance with the WED was suboptimal, and significant attrition in compliance occurs over time," Faisal Siddiqi, MD, of the University of Maryland in Baltimore, told MedPage Today during a poster presentation at the Heart Failure Society of America meeting.

"Poor compliance leaves this high-risk population vulnerable to sudden cardiac death. Our results suggest that patients who meet traditional criteria for an implantable cardioverter-defibrillator (ICD) require close monitoring to ensure compliance with their WED. Efforts also should be directed at expediting ICD implantation," Siddiqi said.

WED has gained acceptance among cardiologists as a useful bridge to definitive therapy with an ICD. However, the device's ability to prevent sudden death hinges on patient compliance, which has not been examined carefully.

To address the lack of data, Siddiqi and colleagues retrospectively reviewed records of 31 patients who had received a WED from March 2005 to November 2009. Investigators compared actual patient usage of the device with the prescribed number of days and hours.

The study included 21 men and 10 women who had a mean age of 55 and mean left ventricular ejection fraction of 36%. Three-fourths of the patients had cardiomyopathy, 20 had a history of ventricular arrhythmias, and 11 had previously received an ICD.

Prescribed usage of the WED averaged about 50 days. Siddiqi and colleagues tracked patient compliance with the prescription across three calendar months.

When calculated by actual-versus-prescribed days of WED use, compliance was 91% for the first calendar month, 80% for the second month, and 67% for the third month.

A similar pattern emerged from calculations of actual-versus-prescribed hours of use, reaching a peak of 83% during the first month, then declining to 66% in the second month, and 52% in the third month.

A review of electrocardiograms stored in the WED showed no evidence of clinically significant arrhythmias during the time the patients wore the device.

Siddiqi reported that 12 of the 31 patients eventually received an ICD and one patient had a heart transplant. Four patients died, one of whom died suddenly while not wearing a prescribed WED. Six patients improved clinically, and a permanent risk of sudden death could not be established.

Two patients continued to use a prescribed WED at the time of the data analysis, and six patients were lost to follow-up.

"Physicians who care for these patients need to be aware that the patients require close monitoring throughout the time the WED is in use," said Siddiqi. "Although the findings represent a small group of patients from a single center, they show that attrition begins during the first weeks of use and increases over time."

"Even though the patients have a life-threatening condition, physicians can't assume that the patients are using the WEDs as prescribed," he added.

Siddiqi and co-investigators declared that they had no relevant disclosures.

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